1. Field
The invention relates to flame retardant molding composition that can be used to make molded articles with good physical and mechanical properties.
2. Description of the Related Technology
Thermoplastic resin blends are commonly used in electronic and non-electronic devices. Researchers have tried to achieve resins that have good heat resistance, impact strength, dimensional stability, and thermal stability. Polyphenylene ether resins have many of these qualities; however it has poor processability. To improve its processability, polyphenylene ether resins may be blended with styrene resins. While imparting better processabilitty, this combination typically results in reduced impact strength. Attempts to further improve the impact strength in such compositions have been made. However, they usually result in the deterioration of surface gloss and processability.
Flame retardant thermoplastic resin blends are required in some electronic products. A widely known method for imparting flame retardancy is the addition of a halogen-containing compound with an optional antimony catalyst. The inclusion of a halogen containing compound for flame retardancy may make the resin toxic. Therefore, non-halogenated compounds for use as flame retardants are desirable.
Cyclic alkyl phosphonate ester compounds have been known to impart flame retardancy to some resins. While providing excellent flame retardancy without deteriorating impact strength, known cyclic alkyl phosphonate ester compounds have poor thermal stability, often resulting in the occurrence of discoloration and yellow streak on the surface of the resin composition when it is subjected to high temperatures. Thus, there is a need to develop a resin with excellent thermal stability which exhibits substantially no discoloration when exposed to heat.